Big names fell early and unexpected teams broke through to steal the spotlight on Day 1 of U.S. Open mixed doubles play, headlining an electric opener packed with upsets and standout performances.

Some of the biggest stars in men's and women's tennis took the court together at the US Open for reimagined mixed doubles competition.

Grand Slam singles champions such as Jannik Sinner, Carlos Alcaraz, Iga Swiatek and Madison Keys will be playing for extra money — $1 million to the winning duo — and trying to get their hands on a trophy in the U.

The new event wanted to use singles stars to put mixed doubles on a pedestal. Two masters of the discipline have stolen the show.

Carlos Alcaraz, Novak Djokovic and Alexander Zverev are set to play along with Iga Swiatek and 45-year-old veteran Venus Williams when the US Open mixed doubles takes centre stage like never before. Instead of being crammed in amid the singles and doubles matches at the main draw event,

In the U.S. Open, the format is being redesigned as a popularity contest engineered to generate buzz.

Williams is a longtime resident of Palm Beach Gardens while Opelka has lived in the Delray Beach/Boca Raton area since he was a teenager.